There would be a slight difference in CPU usage, meaning the ultimate will be less in use since it's more powerful. But again, only a slight difference.
For me, I only bought the ultimate configuration because the refurb store never has any models with 4gb ram and 256gb ssd without the upgraded processor. I was thinking of going for the 4gb/128gb configuration but I decided to opt for the higher capacity, and it was a good enough price so I jumped on it.